Tissue retraction system

ABSTRACT

A tissue retraction system comprising a drive gear coupled to a shaft. The tissue retraction system includes a first plurality of linking members located along a second axis and configured to rotate along the second axis based on contact with the drive gear as the drive gear is rotated. The tissue retraction system includes a linking member selector configured to rotate along the first axis, wherein the linking member selector comprises a cylindrical body integrally formed with a handle. The tissue retraction system includes a right arm assembly configured to move along a first trajectory. The tissue retraction system includes a first retractor blade coupled to the right arm assembly. The tissue retraction system includes a left arm assembly configured to move along a second trajectory. The tissue retraction system includes a second retractor blade coupled to the left arm assembly.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a non-provisional patent application claiming thebenefit of priority under 35 U.S.C. 119(e) from U.S. Provisional PatentApplication Ser. No. 62/863,224, filed on Jun. 18, 2019, the entirecontents of which are each hereby expressly incorporated by referenceinto this disclosure as if set forth fully herein.

FIELD

This disclosure describes a tissue retraction system for use during asurgical procedure.

BACKGROUND

A noteworthy trend in the medical community is the move away fromperforming surgery via traditional “open” techniques in favor ofminimally invasive or minimal access techniques. Open surgicaltechniques are less desirable in that they typically require largeincisions and high amounts of tissue displacement to gain access to thesurgical target site, which produces concomitantly high amounts of pain,lengthened hospitalization (increasing health care costs), and highmorbidity in the patient population. Less-invasive surgical techniques(including so-called “minimal access” and “minimally invasive”techniques) are gaining favor due to the fact that they involveaccessing the surgical target site via incisions of substantiallysmaller size with greatly reduced tissue displacement requirements.

Currently available access systems require multiple inputs to actuatecomponents in multiple directions or shifting the anchor point of theretractor from one position to another to create a customized exposureto the target surgical site. There exists a need for an access systemthat enables a surgeon to create a reproducible, customized exposure tothe target surgical site in a faster and less complicated manner.

SUMMARY

In one embodiment, a tissue retraction system includes a drive gearcoupled to a shaft. The drive gear is configured to rotate along a firstaxis based on movement of the shaft. The tissue retraction system alsoincludes a first plurality of linking members located along a secondaxis and configured to rotate along the second axis based on contactwith the drive gear as the drive gear is rotated. The tissue retractionsystem also includes a linking member selector configured to rotatealong the first axis. The linking member selector comprises acylindrical body integrally formed with a handle. The cylindrical bodyincludes at least one protrusion. The tissue retraction system alsoincludes a right arm assembly configured to move along a firsttrajectory based on a corresponding movement of at least two linkingmembers of the first plurality of linking members. The tissue retractionsystem also includes the first retractor blade coupled to the right armassembly. The left arm assembly is configured to move along a secondtrajectory based on a corresponding movement of at least another twolinking members of the first plurality of linking members. The tissueretractor system also includes a second retractor blade coupled to theleft arm assembly.

In another embodiment, a tissue retraction system includes a drive gearcoupled to a shaft. The drive gear is configured to rotate along a firstaxis based on movement of the shaft. The tissue retraction system alsoincludes a first plurality of linking members located along a secondaxis and configured to rotate along the second axis based on contactwith the drive gear as the drive gear is rotated. The tissue retractionsystem a second plurality of linking members located along a third axisand configured to rotate along the third axis based on contact with thedrive gear as the drive gear is rotated. The tissue retraction systemalso includes a linking member selector configured to rotate along thefirst axis. The linking member selector includes a cylindrical bodyintegrally formed with a handle. The cylindrical body includes at leasta first protrusion configured to exert a first force on at least onelinking member of the first plurality of linking members based onselection, via the handle of the linking member selector, of a positioncorresponding to the at least one linking member of the first pluralityof linking members. The cylindrical body includes at least a secondprotrusion configured to exert a second force on at least one linkingmember of the second plurality of linking members based on selection,via the handle of the linking member selector, of a positioncorresponding to the at least one linking member of the second pluralityof linking members. The tissue retraction system also includes a rightarm assembly configured to move along a first trajectory based on acorresponding movement of at least two linking members of the firstplurality of linking members. The tissue retraction system also includesa first retractor blade coupled to the right arm assembly. The tissueretraction system also includes a left arm assembly configured to movealong a second trajectory based on a corresponding movement of at leastanother two linking members of the first plurality of linking members.The tissue retraction system also includes a second retractor bladecoupled to the left arm assembly. The tissue retraction system alsoincludes a center arm configured to move along a third trajectory basedon a corresponding movement of at least two linking members of thesecond plurality of linking members. The tissue retraction system alsoincludes a third retractor blade coupled to the center arm.

In another embodiment, the tissue retraction system includes a drivegear coupled to a shaft. The drive gear is configured to rotate along afirst axis based on movement of the shaft. The tissue retraction systemalso includes a first plurality of linking members located along asecond axis and configured to rotate along the second axis based oncontact with the drive gear as the drive gear is rotated. The tissueretraction system also includes a second plurality of linking memberslocated along a third axis and configured to rotate along the secondaxis based on contact with the drive gear as the drive gear is rotated.The tissue retraction system also includes a linking member selectorconfigured to rotate along the first axis, the linking member selectorcomprising a cylindrical body integrally formed with the handle, whereinthe cylindrical body includes at least a first protrusion configured toexert a first force on at least one linking member of the firstplurality of linking members based on selection, via a handle of thelinking member selector, of a position corresponding to the at least onelinking member of the first plurality of linking members. The firstforce on the at least one linking member causes a coupling between theat least one linking member of the first plurality of linking membersand another linking member of the first plurality of linking members.The cylindrical body includes at least a second protrusion configured toexert a second force on at least one linking member of the secondplurality of linking members based on selection, via a handle of thelinking member selector, of a position corresponding to the at least onelinking member of the second plurality of linking members. The secondforce on the at least one linking member causes a coupling between theat least one linking member of the second plurality of linking membersand another linking member of the second plurality of linking members.The tissue retraction system also includes a right arm assemblyconfigured to move along either a first trajectory or a secondtrajectory. The first trajectory corresponds to a movement of at leasttwo linking members of the first plurality of linking members. Thesecond trajectory corresponds to a movement of at least two linkingmembers of the second plurality of linking members. The tissueretraction system also includes a first retractor blade coupled to theright arm assembly. The tissue retraction system also includes a leftarm assembly configured to move along either the second trajectory or athird trajectory. The third trajectory corresponds to a movement of atleast two other linking members of the first plurality of linkingmembers. The tissue retraction system also includes a second retractorblade coupled to the left arm assembly. The tissue retraction systemalso includes a center arm configured to move along a fourth trajectorybased on a corresponding movement of at least two other linking membersof the second plurality of linking members. The tissue retraction systemalso includes a third retractor blade coupled to the center arm. Thetissue retraction system also includes a post located along a fourthaxis parallel and offset to the first axis. The tissue retraction systemalso includes locking teeth secured to the system at a first end of thepost, where in the post includes at least one tapered surface. Thetissue retraction system also includes an articulating arm connector.The articulating arm connector includes an aperture, a button with atapered surface, and locking teeth. The aperture is configured toreceive the post. The tapered surface of the button is configured tointerface with the at least one tapered surface of the post. The lockingteeth of the post are configured to engage with the locking teethsecured to the system.

BRIEF DESCRIPTION OF THE DRAWINGS

Many advantages of the present invention will be apparent to thoseskilled in the art with a reading of this specification in conjunctionwith the attached drawings, wherein like reference numerals are appliedto like elements and wherein:

FIG. 1 illustrates an exploded view of an assembly, according to anembodiment of the present disclosure;

FIG. 2 illustrates another view of the assembly of FIG. 1 , according toan embodiment of the present disclosure;

FIG. 3 illustrates a portion of the assembly of FIG. 1 , according to anembodiment of the present disclosure;

FIG. 4 illustrates a top view of a portion of the assembly of FIG. 1 ,according to an embodiment of the present disclosure;

FIG. 5 illustrates a bottom view of a portion of the assembly of FIG. 1, according to an embodiment of the present disclosure;

FIG. 6 illustrates a bottom view of a portion of the assembly of FIG. 1, according to an embodiment of the present disclosure;

FIG. 7 illustrates a bottom view of a portion of the assembly of FIG. 1, according to an embodiment of the present disclosure;

FIG. 8 illustrates a bottom view of a portion of the assembly of FIG. 1, according to an embodiment of the present disclosure;

FIG. 9 illustrates a bottom view of a portion of the assembly of FIG. 1, according to an embodiment of the present disclosure;

FIG. 10 illustrates an example pinion assembly according to anembodiment of the present disclosure;

FIG. 11 illustrates an example surgical retractor, according to anembodiment of the present disclosure;

FIG. 12 illustrates an example tissue retraction system, according to anembodiment of the present disclosure;

FIG. 13 illustrates an example tissue retraction system, according to anembodiment of the present disclosure;

FIG. 14 illustrates a top view of the example tissue retraction systemof FIG. 13 , according to an embodiment of the present disclosure;

FIG. 15 illustrates a top view of an example tissue retraction system,according to an embodiment of the present disclosure;

FIG. 16 illustrates a top view of another example tissue retractionsystem, according to an embodiment of the present disclosure.

DETAILED DESCRIPTION

Illustrative embodiments of the invention are described below. In theinterest of clarity, not all features of an actual implementation aredescribed in this specification. It will of course be appreciated thatin the development of any such actual embodiment, numerousimplementation-specific decisions must be made to achieve thedevelopers' specific goals, such as compliance with system-related andbusiness-related constraints, which will vary from one implementation toanother. Moreover, it will be appreciated that such a development effortmight be complex and time-consuming, but would nevertheless be a routineundertaking for those of ordinary skill in the art having the benefit ofthis disclosure. It is furthermore to be readily understood that,although discussed below primarily within the context of spinal surgery,the surgical access system of the present invention may be employed inany number of anatomical settings to provide access to any number ofdifferent surgical target sites throughout the body. It is alsoexpressly noted that, although shown and described herein largely withinthe context of lateral surgery in the lumbar spine, the access system ofthe present invention may be employed in any number of other spinesurgery access approaches, including but not limited to posterior,postero-lateral, anterior, and antero-lateral access, and may beemployed in the lumbar, thoracic and/or cervical spine, all withoutdeparting from the present invention. The surgical access systemdisclosed herein boasts a variety of inventive features and componentsthat warrant patent protection, both individually and in combination.

The surgical access system according to an exemplary embodiment includesa tissue retractor. The retractor described herein has a plurality ofblades configured for insertion through a patient's tissue to a surgicalsite that can be actuated independently or simultaneously. According tothe exemplary embodiment, the plurality of blades may be movedindependently or simultaneously in order to create a surgical corridorwith a customized size determined by the surgeon user. Further, movementof the plurality of blades is directed by a single input source. Inother words, the retractor includes a single input device capable ofcausing movement of all of the blades, regardless of whether the bladesare actuated at the same time or each blade is actuated independently,as opposed to each blade requiring its own input mechanism that onlycontrols movement of that blade.

According to an exemplary embodiment, the capability to actuate theretractor blades independently or simultaneously by a single inputsource is accomplished by allowing the user to select one of a pluralityof different blade actuation modes. For example, the retractor may haveat least five blade actuation modes that are activated by positioning aselector in one of five positions. According to the exemplaryembodiment, the positions may include a right blade actuation position,a left blade actuation position, a combined right blade and left bladeactuation position along a first axis, a combined right blade and leftblade actuation along a second axis, and a posterior blade actuationposition. In one example, the single input source is configured torotate along an axis when selecting one of the five positions.

Examples described herein include subsystems that enable a surgicalretractor, including an assembly, to be used in a surgical procedure. Inone example, the assembly includes a dial that is attachable anddetachable to a shaft. In this example, the shaft is coupled to a drivegear. The drive gear is configured to rotate along a first axis of theassembly based on movement of the dial. In this example, the assemblyalso includes a first linking member that is located along a second axisof the assembly. The first linking member includes a gear and isconfigured to rotate about the second axis based on contact of the gearwith the drive gear as the drive gear is rotated via movement of thedial. By way of example, the gear and the drive gear may be bevel gears.The assembly also includes a second linking member located along thesecond axis. The second linking member is configured to rotate about thesecond axis based on rotation of the drive gear and a coupling betweenthe first linking member and the second linking member. In one example,the coupling between the first linking member and the second linkingmember is based on a mating of a first locking element of the firstlinking member and a second locking element of the second linkingmember. In one example, the assembly includes a linking member selectorthat is configured to rotate about the first axis of the assembly. Thelinking member selector includes a handle for rotating the linkingmember selector to a position corresponding to the first linking member.The linking member selector includes a cylindrical body that isintegrally formed with the handle. The cylindrical body includes anaperture along a longitudinal axis of the cylindrical body. Thecylindrical body also includes a protrusion. The protrusion isconfigured to exert a force on the first linking member based onselection of the position corresponding to the first linking member. Theforce on the first linking member causes the coupling between the firstlinking member and the second linking based on a linear movement of thefirst linking member along the second axis. The aperture is configuredto receive the shaft.

Referring now to the figures, FIG. 1 illustrates an exploded view of anexample assembly 100. The assembly 100 comprises a body 102. The body102 is configured to receive a linking member selector 120 along a firstaxis 112. The linking member selector 120 is configured to receive ashaft 106 that is coupled to a drive gear 108 via a fastener 110. Theshaft 106 is configured to receive a dial 104. The body 102 isconfigured to receive a first linking member 114 along a second axis116. The body 102 includes a nut 160 that is configured to receive thefirst linking member 114 and a second linking member 118 along thesecond axis 116. The second linking member 118 is configured to receivethe first linking member 114. The body 102 is configured to receive athird linking member 130 along a third axis 132. The body 102 isconfigured to receive a center arm 162. The center arm 162 is configuredto receive the third linking member 130 and a fourth linking member 134along the third axis 132. The fourth linking member 134 is configured toreceive the third linking member 130. The body 102 is configured toreceive a fifth linking member 138 along the second axis 116. The body102 includes a nut 164 that is configured to receive the fifth linkingmember 138 and a sixth linking member 140 along the second axis 116. Thesixth linking member 140 is configured to receive the fifth linkingmember 138. The body 102 is configured to receive a seventh linkingmember 142 along the third axis 132. The body 102 includes a nut 166that is configured to receive the seventh linking member 142 and aneighth linking member 144 along the third axis 132. The eighth linkingmember 144 is configured to receive the seventh linking member 142. Thebody includes a post 146 along a fourth axis 198. As shown in FIG. 1 ,the first axis 112 is perpendicular to the second axis 116, and thesecond axis 116 is perpendicular to the third axis 132. Although theseaxes are shown to be perpendicular to one another in this exampleassembly 100, other angles between each of the three axes areenvisioned.

The linking member selector 120 comprises a handle 122 for rotating thelinking member selector 120 about the first axis 112. The linking memberselector 120 comprises a cylindrical body 124 that is integrally formedwith the handle 122. The cylindrical body 124 includes an aperture 126along a longitudinal axis of the cylindrical body 124. The cylindricalbody 124 comprises a plurality of protrusions 128, 129, 135, and 136 asshown in FIG. 1 , and protrusions 137 and 139 not shown in FIG. 1 . Thelinking member selector 120 comprises a pointer 123 and a window 125 foraligning the linking member selector 120 with a position for selectingat least one linking member and for viewing a marking (not shown) on thebody 102 that corresponds with the position. In one example, the pointer123 is configured to align with a position that selects at least onelinking member. In this example, one or more markings (not shown)corresponding to one or more positions for selecting at least onelinking member are located along a perimeter of the body 102. Continuingwith this example, the one or more markings along the perimeter of thebody 102 are visible through the window 125 as the linking memberselector 120 is rotated about the first axis 112 to a given positionassociated with a given marking. In one example, the handle 122 is usedto rotate the linking member selector 120 to a position that selects atleast one linking member of the linking members 114, 130, 138, and 142.Based on a position selected, at least one of the protrusions of theplurality of protrusions 128, 129, 135, 136, 137, and 139 will exert aforce on at least one linking member of the linking members 114, 130,138, and 142.

For example, based on a desired selection of the first linking member114, the linking member selector 120 is rotated about the first axis 112to a given position corresponding to the first linking member 114. As aresult of the selection of the first linking member 114, the protrusion135 will exert a force on the first linking member 114. The forceexerted on the first linking member 114 causes the first linking member114 to move linearly along the second axis 116 from a first position toa second position. In this example, the linear movement of the firstlinking member 114 from the first position to the second position willresult in a coupling between the first linking member 114 and the secondlinking member 118. In another example, based on rotation of the linkingmember selector 120 and a selection of the third linking member 130, theprotrusion 137 (not shown) will exert a force on the third linkingmember 130 that causes the third linking member 130 to move linearlyalong the third axis 132. In this example, the linear movement of thethird linking member 130 from a first position to a second positionalong the third axis 132 will result in a coupling between the thirdlinking member 130 and the fourth linking member 134. In anotherexample, based on rotation of the linking member selector 120 and aselection of the fifth linking member 138, one of the plurality ofprotrusions 128, 129, 135, 136 and 139 (not shown) will exert a force onthe fifth linking member 138 that causes the fifth linking member 138 tomove linearly along the second axis 116. In this example, the linearmovement of the fifth linking member 138 from a third position to afourth position along the second axis 116 will result in a couplingbetween the fifth linking member 138 and the sixth linking member 140.In another example, based on rotation of the linking member selector 120and a selection of the seventh linking member 142, the protrusion 137will exert a force on the seventh linking member 142 that causes theseventh linking member 142 to move linearly along the third axis 132. Inthis example, the linear movement of the seventh linking member 142 froma third position to a fourth position along the third axis 132 willresult in a coupling between the seventh linking member 142 and theeighth linking member 144.

As shown in FIG. 1 , the aperture 126 of the linking member selector 120is configured to receive the shaft 106. In one example, the diameter ofthe aperture 126 and the diameter of the shaft 106 are dimensionedaccordingly to allow the shaft 106 to rotate within the aperture 126 andabout the first axis 112. In one example, rotation of the shaft 106 isaccomplished by movement of the dial 104 when the dial 104 is coupled tothe shaft 106. Rotation of the shaft 106 further causes rotation of thedrive gear 108 and the linking members 114, 130, 138, and 142.

A spring 152 is interposed between the first linking member 114 and thesecond linking member 118. A spring 154 is interposed between thirdlinking member 130 and the fourth linking member 134. A spring 156 isinterposed between the fifth linking member 138 and the sixth linkingmember 140. A spring 158 is interposed between the seventh linkingmember 142 and the eighth linking member 144. In one example, each ofthe springs 152, 154, 156, and 158 are configured to operate ascompression springs. In this example, the springs 152, 154, 156, and 158are configured to provide a predetermined resistance between theadjacent linking members in order to maintain a distance between the twoadjacent linking members that prevents them from coupling with oneanother. Continuing with this example, the springs 152, 154, 156, and158 are also configured to compress based on a force exerted by one ofthe plurality of protrusions 128, 129, 135, 136, 137, and 139 on atleast one of the linking members 114, 130, 138, and 142. For example,two adjacent linking members (e.g., first linking member 114 and secondlinking member 118) are configured to interlock according topredetermined amount of compression on a given spring (e.g., spring 152)according to a force exerted on a given linking member (e.g., linkingmember 114) as a result of the position of the linking member selector120.

The nut 160 comprises an internal threaded portion that is configured toengage with a threaded portion of the second linking member 118. In oneexample, the linking member selector 120 is rotated to a position thatcorresponds to a selection of the first linking member 114 and therebycauses a coupling between the first linking member 114 and the secondlinking member 118 as described above. In this example, the dial 104 isrotated in a clockwise direction about the first axis 112 and therebycauses a rotation in a clockwise direction of the drive gear 108 aboutthe first axis 112 and a rotation of the first linking member 114 aboutthe second axis 116. Continuing with this example, as a result of thecoupling between the first linking member 114 and the second linkingmember 118, the second linking member 118 is also rotated about thesecond axis 116. Based on contact with the internal threaded portion ofthe nut 160 and the threaded portion of the second linking member 118,the rotational movement of the second linking member 118 is converted toa linear movement of the nut 160 along the second axis 116 and away fromthe body 102. In this example, as the dial 104 is rotated in acounter-clockwise direction about the first axis 112, the rotationalmovement of the second linking member 118 is converted to a linearmovement of the nut 160 along the second axis 116 and towards the body102.

The center arm 162 comprises an internal threaded portion that isconfigured to engage with a threaded portion of the fourth linkingmember 134. In one example, the linking member selector 120 is rotatedto a position that corresponds to selection of the third linking member130 and thereby causes a coupling between the third linking member 130and the fourth linking member 134 as described above. In this example,the dial 104 is rotated in a clockwise direction about the first axis112 and thereby causes a rotation in a clockwise direction of the drivegear 108 about the first axis 112 and a rotation of the third linkingmember 130 about the third axis 132. Continuing with this example, as aresult of the coupling between the third linking member 130 and thefourth linking member 134, the fourth linking member 134 is also rotatedabout the third axis 132. Based on contact with the internal threadedportion of the center arm 162 and the threaded portion of the fourthlinking member 134, the rotational movement of the fourth linking member134 is converted to a linear movement of the center arm 162 along thethird axis 132 and away from the body 102. In this example, as the dial104 is rotated in a counter-clockwise direction about the first axis112, the rotational movement of the fourth linking member 134 isconverted to a linear movement of the center arm 162 along the thirdaxis 132 and towards the body 102.

The nut 164 comprises an internal threaded portion that is configured toengage with a threaded portion of the sixth linking member 140. In oneexample, the linking member selector 120 is rotated to a position thatcorresponds to a selection of the fifth linking member 138 and therebycauses a coupling between the fifth linking member 138 and the sixthlinking member 140 as described above. In this example, the dial 104 isrotated in a clockwise direction about the first axis 112 and therebycauses a rotation in a clockwise direction of the drive gear 108 aboutthe first axis 112 and a rotation of the fifth linking member 138 aboutthe second axis 116. Continuing with this example, as a result of thecoupling between the fifth linking member 138 and the sixth linkingmember 140, the sixth linking member 140 is also rotated about thesecond axis 116. Based on contact with the internal threaded portion ofthe nut 164 and the threaded portion of the sixth linking member 140,the rotational movement of the sixth linking member 140 is converted toa linear movement of the nut 164 along the second axis 116 and away fromthe body 102. In this example, as the dial 104 is rotated in acounter-clockwise direction about the first axis 112, the rotationalmovement of the second linking member 138 is converted to a linearmovement of the nut 164 along the second axis 116 and towards the body102.

The nut 166 comprises an internal threaded portion that is configured toengage with a threaded portion of the eighth linking member 144. In oneexample, the linking member selector 120 is rotated to a position thatcorresponds to a selection of the seventh linking member 142 and therebycauses a coupling between the seventh linking member 142 and the eighthlinking member 144 as described above. In this example, the dial 104 isrotated in a clockwise direction about the first axis 112 and therebycauses a rotation in a clockwise direction of the drive gear 108 aboutthe first axis 112 and a rotation of the seventh linking member 142about the third axis 132. Continuing with this example, as a result ofthe coupling between the seventh linking member 142 and the eighthlinking member 144, the eighth linking member 144 is also rotated aboutthe third axis 132. Based on contact with the internal threaded portionof the nut 166 and the threaded portion of the eighth linking member144, the rotational movement of the eighth linking member 144 isconverted to a linear movement of the nut 166 along the third axis 132and towards the body 102. In this example, as the dial 104 is rotated ina counter-clockwise direction about the first axis 112, the rotationalmovement of the eighth linking member 144 is converted to a linearmovement of the nut 166 along the third axis 132 and away from the body102.

In one example, the linking member selector 120 is rotated to a positionon the body 102 that corresponds to a selection of the first linkingmember 114 and a selection of the fifth linking member 138. In thisexample, a first force is exerted on the first linking member 114 by oneof the protrusions 128, 129, 135, 136, and 139 and a second force isexerted on the fifth linking member 138 by another one of theprotrusions 128, 129, 135, 136, and 139. As described above, the firstforce causes a coupling between first linking member 114 and the secondlinking member 118. Also as described above, the second force causes acoupling between the fifth linking member 138 and the sixth linkingmember 140. Continuing with this example, the dial 104 is rotated in aclockwise direction about the first axis 112 and thereby causes rotationin a clockwise direction of the drive gear 108 about the first axis 112and a simultaneous rotation of the first linking member 114 and thefifth linking member 138 about the second axis 116. In this example, asa result of the coupling between the first linking member 114 and thesecond linking member 118 and the coupling between the fifth linkingmember 138 and the sixth linking member 140, the second linking member118 and the sixth linking member 140 are also rotated about the secondaxis 116. Based on contact with the internal threaded portion of the nut160 and the threaded portion of the second linking member 118 andcontact with the internal threaded portion of the nut 164 and thethreaded portion of the sixth linking member 140, the rotationalmovements of the second linking member 118 and the sixth linking member140 are converted to linear movements of the nut 160 and the nut 164along the second axis 116 and away from the body 102. In this example,as the dial 104 is rotated in a counter-clockwise direction about thefirst axis 112, the rotational movements of the second linking member118 the sixth linking member 140 are converted to linear movements ofthe nut 160 and the nut 164 along the second axis 116 and towards thebody 102.

As shown in FIG. 1 , a post 146 is coupled to the body 102. Ananti-rotation feature 150 is secured to the body 102 at a first end ofthe post 146. In one example, the post 146 is configured to attach theassembly 100 to an external arm (not shown) for securing the assembly100 in a fixed position during a surgical procedure. In one example, theexternal arm is an articulating arm comprising one or more sectionsconnected by joints that allow each section to bend or turnindependently in different directions.

FIG. 2 illustrates an assembled view of the assembly 100 of FIG. 1 . Asshown in FIG. 2 , the linking member selector 120 is in a positioncorresponding to the seventh linking member 142 (not shown). In thisposition, based on rotation of the dial 104 about the first axis 112,the rotational movement of the drive gear 108 (not shown) about thefirst axis 112, the rotational movement of the seventh linking member142 about the third axis 132, and the rotational movement of the eighthlinking member 144 (not shown) about the third axis 132 will beconverted to a linear movement of the nut 166 along the third axis 132as described above.

FIG. 3 illustrates a view of the linking member selector 120 of FIG. 1 .As shown in FIG. 3 , the linking member selector 120 comprises aplurality of protrusions 128, 129, 135, 136, 137, and 139 located alongthe cylindrical body 124. In one example, the protrusion 137 isconfigured to extend along the entire length of the cylindrical body124. In this example, a contact position of the third linking member 130along the first axis 116 and a contact position of the seventh linkingmember 142 along the first axis 116 are at a position along the firstaxis 112 that is above the contact positions corresponding to each ofthe protrusions 135, 136, and 139. The difference between the contactposition of the third linking member 130 along the first axis 112 andthe contact positions corresponding to each of the protrusions 135, 136,and 139 along the first axis 112 enables only the protrusion 137 toexert a force on the contact position of the third linking member 130.The force exerted on the third liking member 130 results in a couplingbetween the third linking member 130 and the fourth linking member 134as described above. Similarly, the difference between the contactposition of the seventh linking member 142 along the first axis 112 andthe contact position corresponding to each of the protrusions 135, 136,and 139 along the first axis 112 enables only the protrusion 137 toexert a force on the contact position of the seventh linking member 142.The force exerted on the seventh linking member 142 results in acoupling between the seventh linking member 142 and the eighth linkingmember 144 as described above.

In another example, a contact position of the first linking member 114along the first axis 112 and a contact position of the fifth linkingmember 138 along the first axis 112 are at the same position along thefirst axis 112 as the contact positions corresponding to the protrusions135, 136, and 139. In this example, the corresponding positions enableonly the protrusions 135, 136, and 139 to exert a force on the contactposition of the first linking member 114. The force exerted on the firstlinking member 114 results in a coupling between the first linkingmember 114 and the second linking member 118 as described above.Similarly, the same position along the first axis 112 of the contactposition of the fifth linking member 138 and the contact positionscorresponding to the protrusions 135, 136, and 139 enable only theprotrusions 135, 136, and 139 to exert a force on the contact positionof the fifth linking member 138. The force exerted on the fifth linkingmember 138 results in a coupling between the fifth linking member 138and the sixth linking member 140 as described above.

FIG. 4 illustrates a top view of a subset of the components of theassembly 100 in FIG. 1 . As shown in FIG. 4 , the linking memberselector 120 has been rotated to a position corresponding to the firstlinking member 114 (not shown). The first linking member 114 comprises afirst gear 168 located along the second axis 116 and configured torotate based on contact with the drive gear 108 (not shown) of FIG. 1 asthe drive gear 108 is rotated. The first linking member 114 includeslocking teeth 170 extending from the first gear 168. The second linkingmember 118 comprises locking teeth 172 extending from the second linkingmember 118. The locking teeth 172 extending from the second linkingmember 118 are configured to interlock with the locking teeth 170extending from the first gear 168 based on a linear movement of thefirst linking member 118 from a first position along the second axis 116to a second position along the second axis 116, as shown in FIG. 4 . Inthis scenario, the locking teeth 172 extending from the second linkingmember 118 are configured to separate from the locking teeth 170extending from the first gear 168 based on a linear movement of thefirst linking member 118 from the second position along the second axis116 to a first position along the second axis 116. In one example, thesecond linking member 118 comprises a leadscrew configured to translatea rotational movement into a linear movement based on rotation of thedrive gear 108 and the coupling between the first linking member 114 andthe second linking member 118.

FIG. 5 illustrates a bottom view that corresponds to the top view ofFIG. 4 . As shown in FIG. 5 , the third linking member 130 comprises asecond gear 180 located along the third axis 132 and configured torotate based on contact with the drive gear 108 (not shown) of FIG. 1 asthe drive gear 108 is rotated. The third linking member 130 includeslocking teeth 182 extending from the second gear 180. The fourth linkingmember 134 comprises locking teeth 184. The locking teeth 184 extendingfrom the fourth linking member 134 are configured to interlock with thelocking teeth 182 extending from the second gear 180 based on a linearmovement of the third linking member 130 from a first position along thethird axis 132 to a second position along the third axis 132. Thelocking teeth 184 extending from the fourth linking member 134 areconfigured to disengage from the locking teeth 182 extending from thesecond gear 180 based on a linear movement of the third linking member130 from the second position along the third axis 132 to the firstposition along the third axis 132. In one example, the fourth linkingmember 134 comprises a leadscrew configured to translate a rotationalmovement into a linear movement based on rotation of the drive gear 108and the coupling between the third linking member 130 and the fourthlinking member 134.

As shown in FIG. 5 , the fifth linking member 138 comprises a third gear174 located along the second axis 116 and configured to rotate based oncontact with the drive gear 108 of FIG. 1 as the drive gear 108 isrotated. The fifth linking member 138 includes locking teeth 176extending from the third gear 174. The sixth linking member 140 alsoincludes locking teeth 178. The locking teeth 178 extending from thesixth linking member 140 are configured to interlock with the lockingteeth 176 extending from the third gear based on a linear movement ofthe fifth linking member 138 from a third position along the second axis116 to a fourth position, as shown in FIG. 5 , along the second axis116. The locking teeth 176, 178 are configured to disengage based on alinear movement of the fifth linking member 138 from the fourth positionalong the second axis 116 to the third position along the second axis116.

As shown in FIG. 5 , the seventh linking member 142 comprises a fourthgear 186 located along the third axis 132 and configured to rotate basedon contact with the drive gear 108 of FIG. 1 as the drive gear 108 isrotated. The seventh linking member 142 includes locking teeth 188extending from the fourth gear 186. The eighth linking member 144 alsocomprises locking teeth 190. The locking teeth 188, 190 are configuredto interlock based on a linear movement of the seventh linking member142 from a third position along the third axis 132 to a fourth positionalong the third axis 132. The locking teeth 188, 190 are configured todisengage based on a linear movement of the seventh linking member 142from the fourth position along the third axis 132 to the third positionalong the third axis 132.

FIG. 6 illustrates a bottom view of a subset of the components of theassembly 100 in FIGS. 1 and 5 . As shown in FIG. 6 , the linking memberselector 120 has been rotated to a position corresponding to the thirdlinking member 130. In this scenario, the locking teeth 184 extendingfrom the fourth linking member are configured to interlock with thelocking teeth 182 extending from the second gear 180 based on a linearmovement of the third linking member 130 from a first position along thethird axis 132 to a second position, as shown in FIG. 6 , along thethird axis 132. In this scenario, the locking teeth 182, 184 areconfigured to disengage based on a linear movement of the third linkingmember 130 from the second position along the third axis 132 to thefirst position along the third axis 132.

FIG. 7 illustrates a bottom view of a subset of the components of theassembly 100 in FIGS. 1 and 5 . As shown in FIG. 7 , the linking memberselector 120 has been rotated to a position corresponding to the fifthlinking member 138. In this scenario, the locking teeth 176, 178 areconfigured to interlock based on a linear movement of the fifth linkingmember 138 from a third position along the second axis 116 to a fourthposition, as shown in FIG. 7 , along the second axis 116. In thisscenario, the locking teeth 176, 178 are configured to disengage basedon a linear movement of the fifth linking member 138 from the fourthposition along the second axis 116 to a third position along the secondaxis 116.

FIG. 8 illustrates a bottom view of a subset of the components of theassembly 100 in FIGS. 1 and 5 . As shown in FIG. 8 , the linking memberselector 120 has been rotated to a position corresponding to the seventhlinking member 142. In this scenario, the locking teeth 190 extendingfrom 144 are configured to interlock with the locking teeth 188extending from the seventh linking member 142 based on a linear movementof the seventh linking member 142 from a third position along the thirdaxis 132 to a fourth position, as shown in FIG. 8 , along the third axis132. In this scenario, the locking teeth 188, 190 are configured todisengage based on a linear movement of the seventh linking member 142from the fourth position along the third axis 132 to the third positionalong the third axis 132.

FIG. 9 illustrates a bottom view of a subset of the components of theassembly 100 in FIGS. 1 and 5 . As shown in FIG. 9 , the linking memberselector 120 has been rotated to a position corresponding to the firstlinking member 114 and the fifth linking member 138. In this scenario,the locking teeth 172 extending from the second linking member 118 areconfigured to interlock with or disengage from the locking teeth 170extending from the first gear 168 as described above. Further, in thisscenario, the locking teeth 178 extending from the sixth linking member140 are configured to interlock with or disengage from with the lockingteeth 176 extending from the third gear 174 as described above.

FIG. 10 illustrates an example pinion sub-assembly 1000. The pinionsub-assembly 1000 comprises a linking member 1002, a spring 1004, a gear1006, and a retaining element 1010. The gear 1006 comprises lockingteeth 1008. The linking member 1002 is configured to receive the spring1004, the gear 1006, and the retaining element 1010. The retainingelement 1010 is configured to retain the spring 1004 and the gear 1006from advancing past a given position along the linking member 1002.

In one example, the linking members 114, 130, 138, and 142, as describedabove, comprise all of the components of the pinion sub-assembly 1000.In this example, the linking member 1002 operates in a similar manner asdescribed with respect to the linking members 114, 130, 138, and 142.Continuing with this example, the gear 1006 and the locking teeth 1008also operate in a similar manner as described with the first gear 168and the locking teeth 170, the second gear 180 and the locking teeth182, the third gear 174 and the locking teeth 176, and the fourth gear186 and the locking teeth 188, respectively. Further, in this example,the spring 1004 is configured to compress based on a force exerted by aprotrusion (e.g., one of the protrusions 128, 129, 135, 136, 137, and139 of FIG. 3 ) on the linking member 1002 (e.g., one of the linkingmembers 114, 130, 138, 142 of FIG. 1 ) and based on a rotationalposition of the locking teeth 1008 with respect to the locking teeth ofanother linking member.

In one scenario, referring to FIG. 5 , if the tips of the locking teeth170 and the tips locking teeth 172 are in a given rotational positionalong the second axis 116 as the first linking member 114 is movedlinearly along the first axis 116 towards the second linking member 118,then it is possible that the locking teeth 170 and 172 will be unable tointerlock with one another as shown in FIG. 5 . Further, it is alsopossible that the linking member selector 120 could also becometemporarily stuck in this position based on the tips of the lockingteeth 170 and 172 preventing the locking teeth 170 and 172 frominterlocking. In order to overcome this scenario, referring back to FIG.10 , the spring 1004 is compressed as the linking member 1002 is movedalong a linear axis towards another linking member while the tips of thelocking teeth 1008 encounter the tips of the locking teeth of anotherlinking member at a rotational position that prevents the locking teeth1008 from interlocking with the locking teeth of another linking member.In this scenario, upon a rotation of the dial 104 and the drive gear108, the locking teeth 1008 (e.g., the locking teeth 170 of FIG. 5 )would rotate about an axis just enough where the tips of the lockingteeth 1008 are no longer in direct contact with the tips of the lockingteeth corresponding to another linking member. Continuing with thisscenario, based on a rotational movement of the linking member 1002, thestored mechanical energy in the spring 1004 would be released andthereby cause the linking member 1002 (e.g., the linking member 114 ofFIG. 5 ) to further move along the linear axis to a given position thatenables the locking teeth 1008 (e.g., the locking teeth 170 of FIG. 5 )to interlock with the locking teeth (e.g., the locking teeth 172 of FIG.5 ) of another linking member (e.g., the linking member 118 of FIG. 5 ).

FIG. 11 illustrates an example surgical retractor 200. The surgicalretractor 200 comprises the assembly 100 of FIG. 1 , a right armassembly 202, and a left arm assembly 204. As shown in FIG. 11 , theright arm assembly 202 comprises a channel 206. The channel 206 isconfigured to receive a pin 208 that is coupled to the nut 160 of FIG. 1. The right arm assembly 202 comprises an aperture for receiving a pin210 that is coupled to the nut 166 of FIG. 1 . The left arm assembly 204comprises a channel 212. The channel 212 is configured to receive a pin214 that is coupled to nut 164 of FIG. 1 . The left arm assembly 204comprises an aperture for also receiving the pin 210 that is coupled tothe nut 166 of FIG. 1 .

In one example, based on the position of linking member selector 120corresponding to first linking member 114 (not shown) and rotation ofthe dial 104 as described above, the nut 160 is configured to move awayfrom or towards the body 102 about the second axis 116. In this example,the right arm assembly 202 is configured to move away from or towardsthe body 102 based on the force exerted by the pin 208 on the right armassembly 202 in addition to the right arm assembly 202 being configuredto pivot around the pin 210.

In one example, based on the position of linking member selector 120corresponding to seventh linking member 142 (not shown) and rotation ofthe dial 104 as described above, the nut 166 is configured to move awayfrom or towards the body 102 about the third axis 132. In this example,the right arm assembly 202 and left arm assembly 204 are configured tomove away from or towards the body 102 based on the force exerted by thepin 210 on the right arm assembly 202 and the left arm assembly 204.

In one example, based on the position of linking member selector 120corresponding to fifth linking member 138 (not shown) and rotation ofthe dial 104 as described above, the nut 164 is configured to move awayfrom or towards the body 102 along the second axis 116. In this example,the left arm assembly 204 is configured to move away from or towards thebody 102 based on the force exerted by the pin 214 on the left armassembly 204 in addition to the left arm assembly 204 being configuredto pivot around the pin 210.

In one example, based on the position of linking member selector 120corresponding to first linking member 114 and the fifth linking member138 (not shown) and rotation of the dial 104 as described above, the nut160 and the nut 164 are configured to move away from or towards the body102 along the second axis 116. In this example, the right arm assembly202 and the left arm assembly 204 are configured to move away from ortowards the body 102 based on the force exerted by the pin 208 on theright arm assembly 202, the force exerted by the pin 214 on the left armassembly 204, the right arm assembly 202 being configured to pivotaround the pin 210, and the left arm assembly 204 being configured topivot around the pin 210. In one example, the right arm assembly 202,the left arm assembly 204, and the center arm 162 are each configured toreceive a retractor blade for use during a surgical procedure.

FIG. 12 illustrates the example surgical retractor 200 and an examplearticulating arm connector 300. The articulating arm connector 300comprises a button 302, an aperture 304, and locking teeth 306.

The aperture 304 is configured to receive the post 146 along the fourthaxis 198. The locking teeth 306 are configured to interlock with thelocking teeth 150. As shown in FIG. 12 , the articulating arm connector300 is configured to attach to a single point of the surgical retractor200. A single point of attachment to the surgical retractor 200 mayreduce the time needed during a surgical procedure.

The button 302 is spring loaded in the engaged state. The button 302also has a lead in chamfer (not shown) allowing it to depress whenaperture 304 receives the post 146. This allows the articulating armconnector 300 to be attached to the surgical retractor 200 withouthaving to press the button 302. The button 302 has a mating taperedsurface that interfaces with the tapered cut of the post 146. That taperpulls the parts together into other tapers and thereby eliminating anymovement between the articulating arm connector 306 and the surgicalretractor 200. To detach the articulating arm connector 300 from thesurgical retractor 200, the button is pressed and the articulating armconnector 300 is separated from the surgical retractor 200. In oneexample, the articulating arm connector 300 utilizes tapers to reduceplay in all three planes (e.g., x, y, and z) for a secure fit.

FIG. 13 illustrates the example surgical retractor 200 with retractorblades 402, 404, and 406 in an open position. As described above, theexample surgical retractor 200 comprises the assembly 100 of FIG. 1 .

In one embodiment, the surgical retractor 200 includes a first retractorblade 402 coupled to the right arm assembly 202, a second retractorblade 404 coupled to the left arm assembly 204, and third retractorblade 406 coupled to the center arm 162. In one example, the surgicalretractor 200 includes a drive gear (e.g., drive gear 108 of FIG. 1 )coupled to a shaft (e.g., shaft 106 of FIG. 1 ). The drive gear isconfigured to rotate along a first axis (e.g., first axis 112 of FIG. 1) based on movement of the shaft, as described above in reference toFIGS. 1-9 .

In one example, the surgical retractor 200 includes a first plurality oflinking members (e.g., linking members 114, 118, 138, and 140 of FIG. 1) that are located along a second axis (e.g., second axis 116 of FIG. 1). The first plurality of linking members are configured to rotate alongthe second axis based on contact with the drive gear as the drive gearis rotated.

In one example, the first plurality of linking members located along thesecond axis comprises a first linking member (e.g., linking member 114),a second linking member (e.g., linking member 118), a third linkingmember (e.g., linking member 138), and a fourth linking member (e.g.,linking member 140). In this example, a coupling between the firstlinking member and the second linking member is based on a linearmovement of the first linking member from a first position along thesecond axis to a second position along the second axis, as shown inFIGS. 4 and 5 . Continuing with this example, a coupling between thethird linking member and the fourth linking member is based on a linearmovement of the third linking member from a third position along thesecond axis to a fourth position along the second axis, as shown in FIG.7 .

In one example, the first linking member comprises a first gear (e.g.,first gear 168 of FIG. 5 ) located along the second axis and configuredto rotate based on contact with the drive gear as the drive gear isrotated. The first linking member also comprises a first locking element(e.g., locking teeth 170 of FIG. 5 ) associated with the first gear.Continuing with this example, the second linking member comprises asecond locking element (e.g., locking teeth 172 of FIG. 5 ) configuredto interlock with or disengage from the first locking element. In onescenario, the second locking element is configured to interlock with thefirst locking element based on a linear movement of the first linkingmember from the first position along the second axis to the secondposition along the second axis, as shown in FIGS. 4 and 5 . In thisscenario, the second locking element is configured to disengage from thefirst locking element based on a linear movement of the first linkingmember from the second position along the second axis to the firstposition along the second axis, as shown in FIG. 6 .

In one example, the third linking member comprises a second gear (e.g.,third gear 168 of FIG. 5 ) located along the second axis and configuredto rotate based on contact with the drive gear as the drive gear isrotated. The third linking member also comprises a third locking element(e.g., locking teeth 176 of FIG. 5 ) associated with the second gear.Continuing with this example, the fourth linking member comprises afourth locking element (e.g., locking teeth 178 of FIG. 5 ) configuredto interlock with or disengage from the third locking element. In onescenario, the fourth locking element is configured to interlock with thethird locking element based on a linear movement of the third linkingmember from the third position along the second axis to the fourthposition along the second axis, as shown in FIG. 7 . In this scenario,the fourth locking element is configured to disengage from the thirdlocking element based on a linear movement of the third linking memberfrom the fourth position along the second axis to the third positionalong the second axis, as shown in FIG. 8 .

In one example, the surgical retractor 200 includes a first spring(e.g., spring 1004 of FIG. 10 ) interposed between the first linkingmember and the second linking member. In one example, the surgicalretractor 200 also includes a second spring (e.g., spring 1004 of FIG.10 ) interposed between the third linking member and the fourth linkingmember.

In one example, the surgical retractor 200 includes a linking memberselector (e.g., linking member selector 120 of FIG. 3 ) configured torotate along the first axis. The linking member selector comprises acylindrical body (e.g., cylindrical body 124 of FIG. 3 ) integrallyformed with a handle (e.g., handle 122 of FIG. 3 ). In one example, thecylindrical body includes at least one protrusion (e.g., the protrusions128, 129, 135, 136, 137, and 139 of FIG. 3 ).

In one example, the at least one protrusion of the cylindrical body (isconfigured to exert a force on at least one linking member of the firstplurality of linking members based on selection, via the handle of thelinking member selector, of a position corresponding to the at least onelinking member. In this example, the force on the at least one linkingmember causes a coupling between the at least one linking member andanother linking member of the first plurality of linking members, asdescribed above.

In a second embodiment, the surgical retractor 200 includes a firstplurality of linking members (e.g., linking members 114, 118, 138, and140 of FIG. 1 ) located along a second axis (e.g., second axis 116 ofFIG. 1 ) and configured to rotate along the second axis based on contactwith the drive gear as the drive gear is rotated. Continuing with thisexample, the surgical retractor 200 also includes a second plurality oflinking members (e.g., linking members 130 and 134 of FIG. 1 ) locatedalong a third axis (e.g., third axis 132 of FIG. 1 ) and configured torotate along the third axis based on contact with the drive gear as thedrive gear is rotated.

In one example, the first plurality of linking members located along thesecond axis comprises a first linking member (e.g., linking member 114),a second linking member (e.g., linking member 118), a third linkingmember (e.g., linking member 138), and a fourth linking member (e.g.,linking member 140). In this example, the second plurality of linkingmembers located along the third axis comprises a fifth linking member(e.g., linking member 130) and a sixth linking member (e.g., linkingmember 134). Continuing with this example, a coupling between the firstlinking member and the second linking member is based on a linearmovement of the first linking member from a first position along thesecond axis to a second position along the second axis, as shown inFIGS. 4 and 5 . In this example, a coupling between the third linkingmember and the fourth linking member is based on a linear movement ofthe third linking member from a third position along the second axis toa fourth position along the second axis, as shown in FIG. 7 . In thisexample, a coupling between the fifth linking member and the sixthlinking member is based on a linear movement of the fifth linking memberfrom a first position along the third axis to a second position alongthe third axis, as shown in FIG. 6 .

In one example, the first linking member comprises a first gear (e.g.,first gear 168 of FIG. 5 ) located along the second axis (e.g., secondaxis 116) and configured to rotate based on contact with the drive gearas the drive gear is rotated. The first linking member also comprises afirst locking element (e.g., locking teeth 170 of FIG. 5 ) associatedwith the first gear. Continuing with this example, the second linkingmember comprises a second locking element (e.g., locking teeth 172 ofFIG. 5 ) configured to interlock with or disengage from the firstlocking element. In one scenario, the second locking element isconfigured to interlock with the first locking element based on a linearmovement of the first linking member from the first position along thesecond axis to the second position along the second axis, as shown inFIGS. 4 and 5 . In this scenario, the second locking element isconfigured to disengage from the first locking element based on a linearmovement of the first linking member from the second position along thesecond axis to the first position along the second axis, as shown inFIG. 6 .

In one example, the third linking member comprises a second gear (e.g.,third gear 168 of FIG. 5 ) located along the second axis (e.g., secondaxis 116) and configured to rotate based on contact with the drive gearas the drive gear is rotated. The third linking member also comprises athird locking element (e.g., locking teeth 176 of FIG. 5 ) associatedwith the second gear. Continuing with this example, the fourth linkingmember comprises a fourth locking element (e.g., locking teeth 178 ofFIG. 5 ) configured to interlock with or disengage from the thirdlocking element. In one scenario, the fourth locking element isconfigured to interlock with the third locking element based on a linearmovement of the third linking member from the third position along thesecond axis to the fourth position along the second axis, as shown inFIG. 7 . In this scenario, the fourth locking element is configured todisengage from the third locking element based on a linear movement ofthe third linking member from the fourth position along the second axisto the third position along the second axis, as shown in FIG. 8 .

In one example, the fifth linking member comprises a third gear (e.g.,second gear 180 of FIG. 5 ) located along the third axis (e.g., thirdaxis 132) and configured to rotate based on contact with the drive gearas the drive gear is rotated. The fifth linking member also comprises afifth locking element (e.g., locking teeth 182 of FIG. 5 ) associatedwith the second gear. Continuing with this example, the sixth linkingmember comprises a sixth locking element (e.g., locking teeth 184 ofFIG. 5 ) configured to interlock with or disengage from the fifthlocking element. In one scenario, the sixth locking element isconfigured to interlock with the fifth locking element based on a linearmovement of the fifth linking member from the first position along thethird axis to the second position along the third axis, as shown in FIG.6 . In one scenario, the sixth locking element is configured todisengage from the fifth locking element based on a linear movement ofthe fifth linking member from the second position along the third axisto the first position along the third axis, as shown in FIG. 7 .

In one example, the surgical retractor 200 includes a linking memberselector (e.g., linking member selector 120 of FIG. 3 ) configured torotate along the first axis (e.g., first axis 112 of FIG. 1 ). Thelinking member selector comprises a cylindrical body (e.g., cylindricalbody 124 of FIG. 3 ) integrally formed with a handle (e.g., handle 122of FIG. 3 ). The cylindrical body includes at least a first protrusion(e.g., protrusion 135 of FIG. 3 ) configured to exert a first force onat least one linking member of the first plurality of linking members.The first force is exerted, in part, based on a selection, via thehandle of the linking member selector, of a position corresponding tothe at least one linking member of the first plurality of linkingmembers. In one scenario, the first force exerted on the at least onelinking member causes a coupling between the at least one linking memberof the first plurality of linking members and another linking member ofthe first plurality of linking members, as shown in FIGS. 4, 5, 7, and 9. The cylindrical body also includes at least a second protrusion (e.g.,protrusion 137 of FIG. 3 ) configured to exert a second force on atleast one linking member of the second plurality of linking members. Thesecond force is exerted, in part, based on selection, via the handle ofthe linking member selector, of a position corresponding to the at leastone linking member of the second plurality of linking members. In onescenario, the second force on the at least one linking member causes acoupling between the at least one linking member of the second pluralityof linking members and another linking member of the second plurality oflinking members, as shown in FIGS. 6 and 8 .

In a third embodiment, the surgical retractor 200 includes a firstplurality of linking members (e.g., linking members 114, 118, 138, and140 of FIG. 1 ) located along a second axis (e.g., second axis 116 ofFIG. 1 ) and configured to rotate along the second axis based on contactwith the drive gear as the drive gear is rotated. Continuing with thisexample, the surgical retractor 200 also includes a second plurality oflinking members (e.g., linking members 130, 134, 142, and 144 of FIG. 1) located along a third axis (e.g., third axis 132 of FIG. 1 ) andconfigured to rotate along the third axis based on contact with thedrive gear as the drive gear is rotated.

In one example, the surgical retractor 200 includes a linking memberselector (e.g., linking member selector 120 of FIG. 3 ) configured torotate along the first axis (e.g., first axis 112 of FIG. 1 ). Thelinking member selector comprises a cylindrical body (e.g., cylindricalbody 124 of FIG. 3 ) integrally formed with a handle (e.g., handle 122of FIG. 3 ). The cylindrical body includes at least a first protrusion(e.g., protrusion 135 of FIG. 3 ) configured to exert a first force onat least one linking member of the first plurality of linking members.The first force is exerted, in part, based on a selection, via thehandle of the linking member selector, of a position corresponding tothe at least one linking member of the first plurality of linkingmembers. In one scenario, the first force exerted on the at least onelinking member causes a coupling between the at least one linking memberof the first plurality of linking members and another linking member ofthe first plurality of linking members, as shown in FIGS. 4, 5, 7, and 9). The cylindrical body also includes at least a second protrusion(e.g., protrusion 137 of FIG. 3 ) configured to exert a second force onat least one linking member of the second plurality of linking members.The second force is exerted, in part, based on selection, via the handleof the linking member selector, of a position corresponding to the atleast one linking member of the second plurality of linking members. Inone scenario, the second force on the at least one linking member causesa coupling between the at least one linking member of the secondplurality of linking members and another linking member of the secondplurality of linking members, as shown in FIGS. 6 and 8 .

FIG. 14 illustrates a top view of the surgical retractor 200 andretractor blades 402, 404, and 406 of FIG. 13 in an open or retractedposition. In one example, the right arm assembly 202 is configured tomove along a trajectory 502 based on a corresponding movement of atleast two linking members of the first plurality of linking members. Themovement of the right arm assembly 202 along the trajectory 502 wouldfurther enable the first retractor blade 402 to move along thetrajectory 502. Continuing with this example, the left arm assembly 204is configured to move along a trajectory 504 based on a correspondingmovement of at least another two linking members of the first pluralityof linking members. Similarly, the movement of the left arm assembly 204along the second trajectory 504 would further enable the secondretractor blade 404 to move along the trajectory 504.

In one example, the center arm 162 is configured to move along atrajectory 506 based on a corresponding movement of at least two linkingmembers of the second plurality of linking members. The movement of thecenter arm 162 along the trajectory 506 would further enable the thirdretractor blade 406 to move along the trajectory 506.

In one example, the right arm assembly 202 is configured to move along atrajectory 502 based on a corresponding movement of at least two linkingmembers of the first plurality of linking members and a trajectory 508based on a corresponding movement of at least two linking members of thesecond plurality of linking members. The movement of the right armassembly 202 along the trajectory 502 would further enable the firstretractor blade 402 to move along either the trajectory 502 or thetrajectory 508. Continuing with this example, the left arm assembly 204is configured to move along a trajectory 504 based on a correspondingmovement of at least another two linking members of the first pluralityof linking members and a trajectory 508 based on a correspondingmovement of at least two linking members of the second plurality oflinking members. Similarly, the movement of the left arm assembly 204along the second trajectory 504 would further enable the secondretractor blade 404 to move along either the trajectory 504 or thetrajectory 508.

FIG. 15 illustrates a top view of the surgical retractor 200 andretractor blades 402, 404, and 406 of FIG. 13 in a closed position. Inone example, the surgical retractor 200 and retractor blades 402, 404,and 406 may be advanced, with the blades in a first generally closedposition, over the exterior of an initial dilator (not shown). Once thesurgical retractor 200 is in a predetermined position, a linking memberselector (e.g., linking member selector 124 of FIG. 1 ) and a dial(e.g., dial 104 of FIG. 1 ) may be operated to move the retractor bladesinto a second, open or retracted position to create an operativecorridor to the surgical target site, as shown in FIG. 14 . In onescenario, the linking member selector and the dial may be rotated alonga first axis (e.g., first axis 112 of FIG. 1 ) to enable movement of oneor more of the retractor blades.

FIG. 16 illustrates a top view of another example surgical retractor1600. The surgical retractor 1600 comprises the assembly 100 of FIG. 1 ,a left arm assembly 1602, a right arm assembly 1604, and a center armassembly 1606 and is configured to operate in a similar manner asdescribed above with reference to the surgical retractor 200. Thesurgical retractor 1600 also comprises retractor blades 1612, 1614, and1616. In one example, the surgical retractor 1600 and retractor blades1612, 1614, and 1616 may be advanced, with the blades in a firstgenerally closed position, over the exterior of an initial dilator (notshown). The surgical retractor 1600 also comprises a dial or handle 1608(that is configured to operate in a similar manner to dial 104 of FIG. 1) and a selector 1620 (that is configured to operate in a similar mannerto the linking member selector 124 of FIG. 1 ). The surgical retractor1600 also comprises a first articulation arm attachment 1622 (that isconfigured to operate in a similar manner to the post 146 of FIG. 1 )and a second articulating arm attachment 1624. The surgical retractor1600 also comprises a first splay adjustment feature 1626 and a secondsplay adjustment feature 1628 which may be operated to adjust the angleof the first blade 1612 and second blade 1614, respectively, relative tothe direction of insertion to further customize the exposure to thesurgical site. According to the exemplary embodiment, the 1608 and thedial or handle may be rotated independently of each other along a firstaxis. Rotation of the selector to a designated position determines whichblade or blades will move when the dial or handle is rotated.

The surgical retractor 1600 has a plurality of modes that dictate whichretractor blades 1612, 1614 and 1616 will be actuated by rotation of thedial or handle 1618 while the selector 1620 is in a specific position.In one example, the surgical retractor 1600 is configured to operate inthree modes. In this example, when the selector 1620 is in a firstposition, actuation of the drive gear (not shown) via the dial or handle1618 will move retractor blade 1612 along a first trajectory. Continuingwith this example, when the selector 1620 is in a second position,actuation of the drive gear will move retractor blade 1614 along asecond trajectory. Still continuing with this example, when the selector1620 is in a third position, actuation of the drive gear will move bothretractor blades 1612 and 1614 along the first and second trajectories,respectively.

In another example, the surgical retractor 1600 is configured to operatein four modes. In this example, when the selector 1620 is in a firstposition, actuation of the drive gear via the dial or handle 1618 willmove retractor blade 1612 along a first trajectory. Continuing with thisexample, when the selector 1620 is in a second position, actuation ofthe drive gear will move retractor blade 1614 along a second trajectory.Further continuing with this example, when the selector 1620 is in athird position, actuation of the drive gear will move both retractorblades 1612 and 1614 along the first and second trajectories,respectively. Continuing with this example, when the selector 1620 is ina fourth position, actuation of the drive gear will move the bothretractors blades 1612 and 1614 along a third trajectory. In onescenario, the third trajectory may be perpendicular to the first andsecond trajectories. By way of example only, the first and secondtrajectories may be in the cranial/caudal direction relative to thepatient and the third trajectory may be in the anterior/posteriordirection relative to the patient.

In yet another example, the surgical retractor 1600 is configured tooperate in five modes. In this example, when the selector 1620 is in afirst position, actuation of the drive gear via the dial or handle 1618will move retractor blade 1612 along a first trajectory. Continuing withthis example, when the selector 1620 is in a second position, actuationof the drive gear will move retractor blade 1614 along a secondtrajectory. Continuing with this example, when the selector 1620 is in athird position, actuation of the drive gear will move both retractorblades 1612 and 1614 along the first and second trajectories,respectively. Continuing with this example, when the selector 1620 is ina fourth position, actuation of the drive gear will move the bothretractor blades 1612 and 1614 along a third trajectory. Continuing withthis example, when the linking member selector 1620 is in a fifthposition, actuation of the drive gear will move the retractor blade 1616along the third trajectory. By way of example only, the first and secondtrajectories may be in the cranial/caudal direction relative to apatient and the third and fourth trajectories may be in theanterior/posterior direction relative to the patient.

In one scenario, when closing the surgical retractor 1600 prior toremoving it from a patient, both retractor blades 1612 and 1614 can beclosed (i.e., moved back to their original insertion position) byturning the dial or handle 1618, even if they were moved away from theirinitial position by different lengths. For example, if the retractorblades 1612 and 1614 were moved unequal distances away from theirinitial “closed” position, when the retractor blades 1612 and 1614 arebeing returned to their “closed” position, the selector 1620 may be setto the mode that causes movement of both the retractor blades 1612 and1614 along the first and second trajectories. In this example, the drivegear is actuated based on rotation of the dial or handle 1618 until bothblades are in their initial closed position. The retractor blade thathas the shorter distance to travel will return to its closed positionfirst and then remain there while the retractor blade that was actuatedfarther away is returned to its initial closed position, without adisruption to the rotation of the dial or handle 1618. At this point,based on the retractor blade that is at a shorter distance, theinterlocking teeth on a given arm assembly of either the left armassembly 1602 or the right arm assembly 1604 would begin to ratchet,compressing a spring and then springing back repeatedly, while the otherarm is continued to be pulled in based on rotation of the dial 1618.Once both the left arm assembly 1602 and the right arm assembly 1604 arein a closed position, both arm assemblies will ratchet.

In some instances, it may be desirable to pivot either the retractorblade 1612 or the retractor blade 1614 (or both) outward in order toincrease the volume of the operative corridor (by increasing the distaldimension of the operative corridor). To accomplish this (with respectto blade 16), the dial or handle 1618 may be removed and attached toeither first or second splay adjustment mechanisms 1626 and 1628. In oneexample, the splay adjustment mechanism 1626, 1628 is rotated in aclockwise direction, the blade 1612, 1614 corresponding to the splayadjustment mechanism 1626, 1628 will pivot in a lateral (outward)direction. When rotating the splay adjustment mechanism 1626, 1628 in acounter-clockwise direction, the corresponding blade 1612, 1614 willpivot a lateral (inward) direction. In one example, the first or secondsplay adjustment mechanisms 1626 and 1628 may provide for infinite splay(i.e., the blades may be splayed to any angulation from 0° to a maximumpermissible angulation).

As shown in FIG. 16 , the articulating arm attachment 1624 includes aquick align feature for preliminary engagement of a “poker chip” styleconnector. This feature provides a user with the means to properly andsecurely align the teeth (i.e., peaks and valleys) of the poker chip forintersection single handedly. This feature avoids locking the pokerchips together before their teeth are properly aligned. This can happenwhen the teeth become worn and it is more difficult to align the peeksof one poker chip in the valleys of the other poker chip.

By way of example, the retractor blades may be composed of any materialsuitable for introduction into the human body, including but not limitedto stainless steel, aluminum, titanium, and/or clear polycarbonate, thatwould ensure rigidity during tissue retraction. The retractor blades maybe optionally coated with a carbon fiber reinforced coating to increasestrength and durability. The blades may be optionally constructed frompartially or wholly radiolucent materials (e.g., aluminum, PEEK,carbon-fiber, and titanium) to improve the visibility of the surgeonduring imaging (e.g., radiographic, MRI, CT, fluoroscope, etc.). Theretractor blades may also be composed of a material that would destructwhen autoclaved (such as polymer containing a portion of glassparticles), which may be advantageous in preventing the unauthorizedre-use of the blades (which would be provided to the user in a sterilestate). The retractor blades may be provided in any number of suitablelengths, depending upon the anatomical environment and surgicalapproach, such as (by way of example only) the range from 20 mm to 150mm. Based on this range of sizes, the assembly 100 of FIG. 1 isextremely versatile and may be employed in any of a variety of desiredsurgical approaches, including but not limited to lateral, posterior,postero-lateral, anterior, and antero-lateral, by simply selecting thedesired size retractor blades and attaching them to the surgicalretractor 200.

In one example, the retractor blades may be equipped with variousadditional features or components. By way of example only, one or moreof the retractor blades may be equipped with a retractor extender, suchas a wide retractor extender or a narrow retractor extender. Theretractor extenders extend from the retractor blades to form aprotective barrier to prevent the ingress or egress of instruments orbiological structures (e.g., nerves, vasculature, organs, etc. . . . )into or out of an operative corridor. Depending upon the anatomicalsetting and surgical approach, one or more of the retractor blades maybe equipped with a shim element. In one example, the shim element has adistal tapered region which may be advanced into tissue (e.g. bone, softtissue, etc.) for the purpose of anchoring the retractor blades and/oradvanced into a disc space to distract the adjacent vertebral bodies(thereby restoring disc height). In similar fashion to the retractorextenders, the shim element also forms a protective barrier to preventthe ingress or egress of instruments or biological structures (e.g.,nerves, vasculature, etc.) into or out of the operative corridor.

In one example, the retractor extenders and/or the shim element may bemade out any material suitable for use in the human body, including butnot limited to biologically compatible plastic and/or metal, preferablypartially or wholly radiolucent in nature material (such as aluminum,PEEK, carbon-fibers and titanium). Construction from plastic or thinmetal provides the additional benefit of allowing the shim and/or theretractor extenders to be collapsed into a compressed or low profileconfiguration at the skin level as the element is inserted, and thenexpanded once it is below skin level and within the operative corridor.In another example, the retractor extenders may have symmetric narrowconfigurations and/or broad configurations and/or an asymmetricconfiguration of narrow and broad elements. For example, any or all ofthe retractor extenders may be provided with a lateral section, a narrowconfiguration, and/or a lateral section. The retractor extenders and/orthe shim element may be composed of a material that would destruct whenautoclaved (such as polymer containing a portion of glass particles),which may be advantageous in preventing the unauthorized re-use of theretractor extenders and/or the shim element (which would be provided tothe user in a sterile state). Slits may also be provided on the shim toimprove flexibility. The retractor extenders and/or the shim element mayhave a parabolic concave curvature.

In one example, each of the retractor extenders and/or the shim elementmay be equipped with a mechanism to selectively and releasably engagewith the respective retractor blades. By way of example only, this maybe accomplished by configuring the retractor extenders and/or the shimelement with a tab element capable of engaging with correspondingratchet-like grooves along the inner-facing surfaces of the retractorblades. Each of the retractor extenders and/or the shim element isprovided with a pair of engagement elements having, by way of exampleonly, a generally dove-tailed cross-sectional shape. The engagementelements are dimensioned to engage with receiving portions on therespective retractor blades. In a preferred embodiment, each of theretractor extenders and/or the shim element may be provided with anelongate slot for engagement with an insertion tool. Each tab member isalso equipped with an enlarged tooth element which engages withincorresponding grooves provided along the inner surface of the retractorblades. On the wide retractor extenders, each includes a center portionflanked by a pair of lateral sections, which effectively increase thewidth of the retractor blades.

In another example, any or all of the retractor blades, the retractorextenders, and/or the shim element may be provided with one or moreelectrodes (preferably at or near their distal regions) equipped for usewith a nerve surveillance system, such as, by way of example, the typeshown and described in Int'l Patent App. Ser. Nos. PCT/US02/30617 filedon Sep. 25, 2002, filed on Jul. 11, 2002, Int'l Patent App. Ser. No.PCT/US2008/004427, filed Apr. 3, 2008 (“Neurophysiology MonitoringPatents”) the entire contents of which are each expressly incorporatedby reference herein. Such a nerve surveillance system is capable ofdetecting the existence of (and optionally the distance and/or directionto) neural structures during the retraction of tissue by detecting thepresence of nerves by applying a stimulation signal to electrodes andmonitoring the evoked EMG signals from the myotomes associated with thenerves in the vicinity of the retractor blades. In so doing, the systemas a whole (including the surgical retractor 200) may be used to form anoperative corridor through (or near) any of a variety of tissues havingsuch neural structures, particularly those which, if contacted orimpinged, may otherwise result in neural impairment for the patient. Inthis fashion, the access system of the surgical retractor 200 may beused to traverse tissue that would ordinarily be deemed unsafe orundesirable, thereby broadening the number of manners in which a givensurgical target site may be accessed.

Any of the features or attributes of the above described embodiments andvariations can be used in combination with any of the other features andattributes of the above described embodiments and variations as desired.Various modifications, additions and other alternative embodiments arepossible without departing from the true scope and spirit. Theembodiments presented herein were chosen and described to provide anillustration of various principles of the present invention and itspractical application to thereby enable one of ordinary skill in the artto utilize the invention in various embodiments and with variousmodifications as are suited to the particular use contemplated. All suchmodifications and variations are within the scope of the presentinvention as determined by the appended claims when interpreted inaccordance with the benefit to which they are fairly, legally, andequitably entitled.

What is claimed is:
 1. A tissue retraction system comprising: a drivegear coupled to a shaft, wherein the drive gear is configured to rotatealong a first axis based on movement of the shaft; a first plurality oflinking members located along a second axis and configured to rotatealong the second axis based on contact with the drive gear as the drivegear is rotated; a linking member selector configured to rotate alongthe first axis, wherein the linking member selector comprises acylindrical body integrally formed with a handle, wherein thecylindrical body includes at least one protrusion; a right arm assemblyconfigured to move along a first trajectory based on a correspondingmovement of at least two linking members of the first plurality oflinking members; a first retractor blade coupled to the right armassembly; a left arm assembly configured to move along a secondtrajectory based on a corresponding movement of at least another twolinking members of the first plurality of linking members; and a secondretractor blade coupled to the left arm assembly.
 2. The system of claim1, wherein the at least one protrusion is configured to exert a force onat least one linking member of the first plurality of linking membersbased on selection, via the handle of the linking member selector, of aposition corresponding to the at least one linking member, wherein theforce on the at least one linking member causes a coupling between theat least one linking member and another linking member of the firstplurality of linking members.
 3. The system of claim 2, wherein thesystem further comprises: a post located along a third axis parallel andoffset to the first axis; and locking teeth secured to the system at afirst end of the post, wherein the post includes at least one taperedsurface.
 4. The system of claim 3, wherein the system further comprises:an articulating arm connector that includes: an aperture; a button witha tapered surface; and locking teeth, wherein the aperture is configuredto receive the post, wherein the tapered surface of the button isconfigured to interface with the at least one tapered surface of thepost, wherein the locking teeth of the articulating arm connector areconfigured to engage with the locking teeth secured to the system at thefirst end of the post.
 5. The system of claim 1, wherein the firstplurality of linking members located along the second axis comprises afirst linking member, a second linking member, a third linking member,and a fourth linking member, wherein a coupling between the firstlinking member and the second linking member is based on a linearmovement of the first linking member from a first position along thesecond axis to a second position along the second axis, wherein acoupling between the third linking member and the fourth linking memberis based on a linear movement of the third linking member from a thirdposition along the second axis to a fourth position along the secondaxis.
 6. The system of claim 5, wherein the first linking membercomprises: a first gear located along the second axis and configured torotate based on contact with the drive gear as the drive gear isrotated; and a first locking element associated with the first gear. 7.The system of claim 6, wherein the second linking member comprises: asecond locking element configured to interlock with or disengage fromthe first locking element, wherein the second locking element isconfigured to interlock with the first locking element based on a linearmovement of the first linking member from the first position along thesecond axis to the second position along the second axis, wherein thesecond locking element is configured to disengage from the first lockingelement based on a linear movement of the first linking member from thesecond position along the second axis to the first position along thesecond axis.
 8. The system of claim 7, wherein the third linking membercomprises: a second gear located along the second axis and configured torotate based on contact with the drive gear as the drive gear isrotated; and a third locking element associated with the second gear. 9.The system of claim 8, wherein the fourth linking member comprises: afourth locking element configured to interlock with or disengage fromthe third locking element, wherein the fourth locking element isconfigured to interlock with the third locking element based on a linearmovement of the third linking member from the third position along thesecond axis to the fourth position along the second axis, wherein thefourth locking element is configured to disengage from the third lockingelement based on a linear movement of the third linking member from thefourth position along the second axis to the third position along thesecond axis.
 10. The system of claim 9, wherein the system furthercompromises: a first spring interposed between the first linking memberand the second linking member; and a second spring interposed betweenthe third linking member and the fourth linking member.
 11. A tissueretraction system comprising: a drive gear coupled to a shaft, whereinthe drive gear is configured to rotate along a first axis based onmovement of the shaft; a first plurality of linking members locatedalong a second axis and configured to rotate along the second axis basedon contact with the drive gear as the drive gear is rotated; a secondplurality of linking members located along a third axis and configuredto rotate along the third axis based on contact with the drive gear asthe drive gear is rotated; a linking member selector configured torotate along the first axis, wherein the linking member selectorcomprises a cylindrical body integrally formed with a handle, whereinthe cylindrical body includes at least a first protrusion configured toexert a first force on at least one linking member of the firstplurality of linking members based on selection, via the handle of thelinking member selector, of a position corresponding to the at least onelinking member of the first plurality of linking members, wherein thecylindrical body includes at least a second protrusion configured toexert a second force on at least one linking member of the secondplurality of linking members based on selection, via the handle of thelinking member selector, of a position corresponding to the at least onelinking member of the second plurality of linking members; a right armassembly configured to move along a first trajectory based on acorresponding movement of at least two linking members of the firstplurality of linking members; a first retractor blade coupled to theright arm assembly; a left arm assembly configured to move along asecond trajectory based on a corresponding movement of at least anothertwo linking members of the first plurality of linking members; a secondretractor blade coupled to the left arm assembly; a center armconfigured to move along a third trajectory based on a correspondingmovement of at least two linking members of the second plurality oflinking members; and a third retractor blade coupled to the center arm.12. The system of claim 11, wherein the first force on the at least onelinking member of the first plurality of linking members causes acoupling between the at least one linking member of the first pluralityof linking members and another linking member of the first plurality oflinking members, wherein the second force on the at least one linkingmember of the second plurality of linking members causes a couplingbetween the at least one linking member of the second plurality oflinking members and another linking member of the second plurality oflinking members.
 13. The system of claim 11, wherein the system furthercomprises: a post located along a fourth axis parallel and offset to thefirst axis; and locking teeth secured to the system at a first end ofthe post, where in the post includes at least one tapered surface. 14.The system of claim 13, wherein the system further comprises: anarticulating arm connector that includes: an aperture; a button with atapered surface; and locking teeth, wherein the aperture is configuredto receive the post, wherein the tapered surface of the button isconfigured to interface with the at least one tapered surface of thepost, wherein the locking teeth of the articulating arm connector areconfigured to engage with the locking teeth secured to the system at afirst end of the post.
 15. The system of claim 11, wherein the firstplurality of linking members located along the second axis comprises afirst linking member, a second linking member, a third linking member,and a fourth linking member, wherein a coupling between the firstlinking member and the second linking member is based on a linearmovement of the first linking member from a first position along thesecond axis to a second position along the second axis, wherein acoupling between the third linking member and the fourth linking memberis based on a linear movement of the third linking member from a thirdposition along the second axis to a fourth position along the secondaxis, wherein the second plurality of linking members located along thethird axis comprises a fifth linking member and a sixth linking member,wherein a coupling between the fifth linking member and the sixthlinking member is based on a linear movement of the fifth linking memberfrom a first position along the third axis to a second position alongthe third axis.
 16. The system of claim 15, wherein the first linkingmember comprises: a first gear located along the second axis andconfigured to rotate based on contact with the drive gear as the drivegear is rotated; and a first locking element associated with the firstgear.
 17. The system of claim 16, wherein the second linking membercomprises: a second locking element configured to interlock with ordisengage from the first locking element, wherein the second lockingelement is configured to interlock with the first locking element basedon a linear movement of the first linking member from the first positionalong the second axis to the second position along the second axis,wherein the second locking element is configured to disengage from thefirst locking element based on a linear movement of the first linkingmember from the second position along the second axis to the firstposition along the second axis.
 18. The system of claim 17, wherein thethird linking member comprises: a second gear located along the secondaxis and configured to rotate based on contact with the drive gear asthe drive gear is rotated; and a third locking element associated withthe second gear.
 19. The system of claim 18, wherein the fourth linkingmember comprises: a fourth locking element configured to interlock withor disengage from the third locking element, wherein the fourth lockingelement is configured to interlock with the third locking element basedon a linear movement of the third linking member from the third positionalong the second axis to the fourth position along the second axis,wherein the fourth locking element is configured to disengage from thethird locking element based on a linear movement of the third linkingmember from the fourth position along the second axis to the thirdposition along the second axis.
 20. The system of claim 19, wherein thefifth linking member comprises: a third gear located along the thirdaxis and configured to rotate based on contact with the drive gear asthe drive gear is rotated; and a fifth locking element associated withthe second gear.
 21. The system of claim 20, wherein the sixth linkingmember comprises: a sixth locking element configured to interlock withor disengage from the fifth locking element, wherein the sixth lockingelement is configured to interlock with the fifth locking element basedon a linear movement of the fifth linking member from the first positionalong the third axis to the second position along the third axis,wherein the sixth locking element is configured to disengage from thefifth locking element based on a linear movement of the fifth linkingmember from the second position along the third axis to the firstposition along the third axis.
 22. A tissue retraction systemcomprising: a drive gear coupled to a shaft, wherein the drive gear isconfigured to rotate along a first axis based on movement of the shaft;a first plurality of linking members located along a second axis andconfigured to rotate along the second axis based on contact with thedrive gear as the drive gear is rotated; a second plurality of linkingmembers located along a third axis and configured to rotate along thesecond axis based on contact with the drive gear as the drive gear isrotated; a linking member selector configured to rotate along the firstaxis, the linking member selector comprising a cylindrical bodyintegrally formed with a handle, wherein the cylindrical body includesat least a first protrusion configured to exert a first force on atleast one linking member of the first plurality of linking members basedon selection, via the handle of the linking member selector, of aposition corresponding to the at least one linking member of the firstplurality of linking members, wherein the first force on the at leastone linking member of the first plurality of linking members causes acoupling between the at least one linking member of the first pluralityof linking members and another linking member of the first plurality oflinking members, wherein the cylindrical body includes at least a secondprotrusion configured to exert a second force on at least one linkingmember of the second plurality of linking members based on selection,via the handle of the linking member selector, of a positioncorresponding to the at least one linking member of the second pluralityof linking members, wherein the second force on the at least one linkingmember of the second plurality of linking members causes a couplingbetween the at least one linking member of the second plurality oflinking members and another linking member of the second plurality oflinking members; a right arm assembly configured to move along either afirst trajectory or a second trajectory, wherein the first trajectorycorresponds to a movement of at least two linking members of the firstplurality of linking members, wherein the second trajectory correspondsto a movement of at least two linking members of the second plurality oflinking members; a first retractor blade coupled to the right armassembly; a left arm assembly configured to move along either the secondtrajectory or a third trajectory, wherein the third trajectorycorresponds to a movement of at least two other linking members of thefirst plurality of linking members; a second retractor blade coupled tothe left arm assembly; a center arm configured to move along a fourthtrajectory based on a corresponding movement of at least two otherlinking members of the second plurality of linking members; a thirdretractor blade coupled to the center arm; a post located along a fourthaxis parallel and offset to the first axis; locking teeth secured to thesystem at a first end of the post, where in the post includes at leastone tapered surface; and an articulating arm connector that includes: anaperture; a button with a tapered surface; and locking teeth, whereinthe aperture is configured to receive the post, wherein the taperedsurface of the button is configured to interface with the at least onetapered surface of the post, wherein the locking teeth of thearticulating arm connector are configured to engage with the lockingteeth secured to the system at the first end of the post.